2294 results about "Semiconductor laser theory" patented technology

An inventive semiconductor laser diode includes a Group III nitride semiconductor layered structure having a major crystal growth plane defined by a non-polar or semi-polar-plane. The Group III nitride semiconductor layered structure includes: a p-type cladding layer and an n-type cladding layer; an In-containing p-type guide layer and an In-containing n-type guide layer held between the p-type cladding layer and the n-type cladding layer; and an In-containing light emitting layer held between the p-type guide layer and the n-type guide layer.

This semiconductor laser apparatus includes a package constituted by a plurality of members, having sealed space inside and a semiconductor laser chip arranged in the sealed space, while surfaces of the members located in the sealed space are covered with a covering agent made of an ethylene-polyvinyl alcohol copolymer.

A semiconductor laser device has a semiconductor laser diode structure made of group III nitride semiconductors having major growth surfaces defined by nonpolar planes or semipolar planes. The semiconductor laser diode structure includes a p-type cladding layer and an n-type cladding layer, a p-type guide layer and an n-type guide layer held between the p-type cladding layer and the n-type cladding layer, and an active layer containing In held between the p-type guide layer and the n-type guide layer. The In compositions in the p-type guide layer and the n-type guide layer are increased as approaching the active layer respectively. Each of the p-type guide layer and the n-type guide layer may have a plurality of In_xGa_1-xN layers (0≦x≦1). In this case, the plurality of In_xGa_1-xN layers may be stacked in such order that the In compositions therein are increased as approaching the active layer.

A substrate is made of SiC. A plurality of AlxGa1-xN patterns (0<=x<=1) is formed on a surface of the substrate and dispersively distributed in an in-plane of the substrate. An AlyGa1-yN buffer layer (0<=y<=1) covers the surface of the substrate and the AlxGa1-xN patterns. A laser structure is formed on the AlyGa1-yN buffer layer. Since the AlGaN buffer layer is grown by using the AlGaN patterns as seed crystals, a dislocation density of a predetermined region in the AlGaN buffer layer can be lowered. The characteristics of a laser structure can be improved by forming the laser structure above the region having a low dislocation density. Since the AlGaN pattern has electric conductivity, the device resistance can be suppressed from being increased.

The optical transmitter includes a semiconductor laser device, and an optical modulator region optically connected to the semiconductor laser device and having the function of modulating the output light from the semiconductor laser device. The operating temperature of the optical modulator region is changed without changing the oscillation wavelength of the semiconductor laser device.

The invention discloses a multi-wavelength high-sensitivity online monitor of multi-component NH3 and H2O based on semiconductor laser absorption spectroscopy. It contains host chassis and open long-path system. Equip power receptacle, switch, fiber connector and data transmission interface. It is characterized in that: there are near-infrared semiconductor laser, semiconductor laser controller, phase-locked amplifier, signal generator, data collecting and controlling module and infrared detector in host chassis which is connected with field optical system by fiber. Open optical system contains send-receive optical telescope and multielement reflector array. Optical telescope has input and output fiber couplers. The device realizes simultaneous testing of gas multi-component by using multi-wavelength and frequency division multi-signal detecting technique.

The present invention provides a surface emitting semiconductor laser, comprising: a semiconductor substrate having sequentially layered thereon a lower multi-layer mirror, an active layer region, and an upper multi-layer mirror that, together with the lower multi-layer mirror, contributes to the formation of a cavity; an upper electrode disposed on an upper layer of the upper multi-layer mirror and provided with an aperture that forms an emission region of a laser beam generated at the active layer region; and a current confinement portion disposed between the upper electrode and the lower multi-layer mirror and provided with an aperture that forms a current path; wherein an aperture diameter of the upper electrode and an aperture diameter of the current confinement portion are determined such that a difference between an optical loss of the cavity in a higher-order lateral mode of the laser beam and an optical loss of the cavity in a fundamental lateral mode of the laser beam becomes a value in the vicinity of a maximum value, and the higher-order lateral mode is suppressed, and at least one of the aperture formed in the upper electrode and the aperture of the current confinement portion is formed into a two-fold symmetrical configuration having long and short axes with respect to arbitrary two axial directions orthogonal to each other in a plane.

A method for forming P-N junctions in a semiconductor wafer includes ion implanting dopant impurities into the wafer and annealing the wafer using a thermal flux laser annealing apparatus that includes an array of semiconductor laser emitters arranged in plural parallel rows extending along a slow axis, plural respective cylindrical lenses overlying respective ones of the rows of laser emitters for collimating light from the respective rows along a fast axis generally perpendicular to the slow axis, a homogenizing light pipe having an input face at a first end for receiving light from the plural cylindrical lenses and an output face at an opposite end, the light pipe comprising a pair of reflective walls extending between the input and output faces and separated from one another along the direction of the slow axis, and scanning apparatus for scanning light emitted from the homogenizing light pipe across the wafer in a scanning direction parallel to the fast axis.

An ultraviolet-light-emitting semiconductor diode comprising an n-type ZnO layer with luminous characteristics formed on a transparent substrate, and a p-type semiconductor layer selected from the group consisting of SrCu2O2, CuAlO2 and CuGaO2, which is formed on the n-type ZnO layer to provide a p-n junction therebetween. The transparent substrate is preferably a single crystal substrate having atomically flat yttria-stabilized zirconia (YSZ) (III) surface. The n-type ZnO layer is formed on the transparent substrate having a temperature of 200 to 1200° C., and the p-type semiconductor layer selected from the group of SrCu2O2, CuAlO2 and CuGaO2 is formed on the n-type ZnO layer. The n-type ZnO layer may be formed without heating the substrate, and then the surface of the ZnO layer may be irradiated with ultraviolet light to promote crystallization therein.

The invention discloses a method for measuring high reflectivity based on self-mixing effect of semiconductor laser which belongs to the technical field of measuring optical elements parameter. The present cavity ringdown technique for determining high reflectivity by measuring ringdown time, using the self-mixing effect of semiconductor laser, improves laser power to coupling efficiency of ringdown cavity by controlling back feedback optical intensity of continuous wave semiconductor laser, greatly improves the signal-noise ratio of cavity outputting signal, thereby improving measuring precision and measuring range of high reflectivity. The methods for controlling back feedback optical intensity which can make the cavity output signal reach the maximum include: inserting a linear polarizer, an attenuation plate, an optical isolator or a variable aperture between the semiconductor laser and the first cavity mirror, or adjusting the pitching of the first cavity mirror, or changing the distance of the laser and the first cavity mirror.

A surface-emitting semiconductor laser includes comprising a substrate, a first mesa that is formed on the substrate and includes at least one mesa capable of emitting laser light, and a second mesa that is formed on the substrate and includes at least one mesa restraining emission of laser light.

A laser light source is provided with a pump light source (1) comprising a semiconductor laser, a solid laser medium (2) which is excited by the semiconductor laser, and multi-mode means for changing at least either a longitudinal mode or a transverse mode of laser oscillation of the solid laser. The oscillation light of the laser medium excited by the light outputted from the pump light source is changed by the multi-mode means into output light (5) having a plurality of oscillation spectra and is outputted, thereby a small, high power, and highly efficient low coherent light source can be realized, and a laser light source having reduced speckle noises can be provided.

In a wavelength monitor that monitors a wavelength of laser light emitted from at least two semiconductor lasers formed in parallel on a semiconductor substrate, the wavelength monitor includes a collimating lens that collimates laser light from each of the semiconductor lasers, an etalon that is arranged so that laser light collimated by the collimating lens is capable of entering and has a periodicity, and a photodetector that receives laser light transmitted through the etalon and detects a light intensity, wherein a beam propagation angle in the etalon of laser light emitted from each of the semiconductor lasers becomes a predetermined angle obtained by formula 1.

The invention discloses an all-optical true random number generator, which comprises an all-optical true random number entropy source, wherein the all-optical true random number entropy source injects output light of a continuous laser device I into a two-section semiconductor laser device through a 3dB optical fiber coupler I and a light attenuator, produces a high-speed chaos self-pulse signal and controls the repeated frequency of the chaos self-pulse signal by adjusting the light injection intensity and the frequency detuning amount. Sampling and subsequent processing are not required; the additional problem caused by signal distortion because of sampling in the prior art is solved; the complexity of a system is greatly reduced; a code rate can be tuned in a large range by changing the light injection intensity and the frequency detuning amount; and the code rate is up to Gbps and can be directly compatible with a light network.

A Q-switched semiconductor laser is supposed to facilitate high-frequency laser modulation with low currents or voltage ranges. According to the invention, a laser of this type consists of at least one continually pumped active medium and two optically coupled resonators at least one of which is passive, both resonators having different mode combs corresponding to the Nonius principle, at least one resonator mirror taking the form of a reflector with strongly dispersive reflection characteristics in the laser wavelength range selected by the double resonator, the index of refraction of the passive resonator and/or reflector capable of being adjusted electronically. With this device, the reflectivity of the laser wavelength can be adjusted in such a way that, with a fixed effective amplification by electrical modulation of the reflectivity of the resonator reflector with strongly dispersive reflection characteristics, the laser threshold can be raised or lowered so as to switch the semiconductor laser on or off.

Method for manufacturing a monolithic integrated semiconductor laser array, wherein each laser DFB grating structure in the array being sampling Bragg grating structure, the grating of each DFB semiconductor laser waveguide in the array is sampling Bragg grating, and the sampling Bragg grating containing equivalent grating corresponding to the common Bragg grating; the mase wavelength of the DFB semiconductor laser is determined by sampling period of the sampling structure of the sampling Bragg grating within the equivalent grating action bandwidth of the sampling Bragg grating, and it is able to change mase wavelength by changing sampling period. The sampling period is increased or decreased by mask plate with various sampling pattern, and various wavelength mases are implemented by closing in or outlying a center wavelength of the DFB laser mase wavelength, thus to implement multi-channel multi-wavelength laser array; the invention implements various complicated equivalent phase-shift with sub-micron stage accuracy, namely corresponding equivalent grating has Lambada/4 phase-shift, Lambada/8 phase-shift and a CPM structure.

A semiconductor laser device includes a substrate made of a nitride-based semiconductor and a waveguide formed on a principal surface of the substrate, wherein the substrate includes a dislocation concentrated region arranged so as to obliquely extend with respect to the principal surface of the substrate, and the waveguide is so formed as to be located above the dislocation concentrated region and also located on a region except a portion where the dislocation concentrated region is present in the principal surface of the substrate.

The semiconductor laser disclosed includes a first conductivity type buffer layer, an active layer and a second conductivity type cladding layer which are sequentially positioned on a first conductivity type semiconductor substrate. The active layer has a laser gain region to which an electric current is injected. The laser gain region having a width varying linearly along a resonating direction is disposed between a high reflection film provided on a facet of a wide side of the laser gain region of the active layer and a low reflection film provided on a facet of a narrow side of the laser gain region of the active layer. The facet of the narrow side is for outputting oscillation beams of a high order mode. This provides a high electrical-to-optical conversion efficiency, and enables the outputting of a large output from a narrow light emission region.

Driving current value needed is obtained through experiment testing calibration method for semiconductor laser to reach certain output power under different temperatures so as to get coincidence relation between temperature and driving current value. The said coincidence relation in list form is inputted into microprocessor by using keyboard input unit. Based on detected operating temperature of LD, changing driving current compensates variation of output power caused by changing temperature in order to realize stable LD output power. The invention also discloses driving power for semiconductor laser operated based on multiple modes in order to realize the disclosed method. The invention is applicable to diversified areas of semiconductor laser being as light source or pump source.